In general, it is necessary to humidify a polymer electrolyte membrane in a fuel cell stack when operating the fuel cell stack. Accordingly, separate membrane humidifiers have been used for exchanging moisture between exhaust gas as wet gas discharged from fuel cell stacks and dry gas supplied from outside air.
Such humidifiers can be classified into bubbler type humidifiers, injection type humidifiers, and adsorbent type humidifiers. However, since fuel cell vehicles have limited packaging spaces, membrane humidifiers, which have relatively small volumes and do not need special power, are generally used. In particular, hollow fiber membrane humidifiers have been used as membrane humidifiers for fuel cells.
Here, a humidifier is typically located at a lower end of a fuel cell stack, in which the humidifier is clamped and connected to the fuel cell stack using a rubber hose or the like.
When air is humidified by the humidifier and supplied to the fuel cell stack, vapor is condensed due to a temperature difference between the humidified air and outside air. In this case, the condensed vapor flows down along a wall surface of the rubber hose, and is accumulated in the humidifier located at the lower end of the fuel cell stack.
Accordingly, when the condensed water is temporarily supplied to the fuel cell stack, the channel passage in the fuel cell stack may be clogged. In addition, if the condensed water freezes during the winter season, the humidification membrane in the humidifier may be damaged due to the volume expansion of water.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.